As a busy mommy, I need my appliances to work. When my dishwasher is not doing the best job, I clean it with plain old white vinegar. I use a children's cup liberated from The Olive Garden. Fill it with about a cup of white vinegar. Place it on the top rack of the dishwasher and run the dishwasher.
This makes my dishwasher work better and life can go on without hand washing dishes!
I do this every three months or so. If there is food debris in the bottom, I may have one of my kids lean in to fish them out.